This study aimed to investigate the effect of dietary graded levels of Aqua Superzyme, Garlen Allicin, and Diamond V (Original XPC) on the chemical composition and histometric parameters of males Nile tilapia Oreochromis niloticus. The carcass composition concerning their DM, CP, and EE contents are increased by age advance, but the ash percentages decreased. At the end of the experiment (16 weeks), DM did not significantly (P≥0.05) influence by all dietary treatments; yet, 0.01% of the diet of either the 1st two substances was responsible for the highest CP and ash percentages and the lowest EE and energy contents. Moreover, 0.5% of the diet of the 3rd substance gave the highest (P≤0.05) level among its tested levels concerning CP and the lowest (P≤0.05) EE and energy contents, but ash was not affected (P≥0.05). The best treatment (highest carcass crude protein and lowest ether extract percentages) was feeding fish the diet containing Diamond V-Original XPC at 0.5% of the diet. The same probiotic at the same level led also to improve most of the histometric characteristics of the dorsal muscles. So, it could recommend the dietary inclusion of the probiotic Diamond V-Original XPC at 0.5% of the tilapia diet.